A conventional vehicle door control system controls locked and unlocked states of every door of a vehicle in accordance with a result of collating identification (ID) codes through duplex communications between a hand-held electronic key serving as a hand-held device and a vehicle-side electronic unit. In this vehicle door control system, a predetermined communication area surrounding the vehicle is set and, in this communication area, a transmitter employed in the vehicle-side unit transmits a request signal typically at predetermined intervals. Thus, the conventional vehicle door control system monitors movements of the holder of the hand-held device as movements approaching the vehicle, getting on the vehicle and getting off from the vehicle.
When the holder of the hand-held device approaches the vehicle in order to get on the vehicle, for example, the holder of the hand-held device enters the predetermined communication area. At that time, the hand-held device transmits a response signal including an ID code to the vehicle-side unit in response to the request signal. The vehicle-side unit determines whether or not the ID code satisfies a predetermined relational condition typically by examining whether or not the ID code matches an ID code registered in advance in the vehicle-side unit. When the ID code satisfies the relational condition, a control signal is supplied to a door locking control device employed in the vehicle-side unit to put every door in an unlock standby state. With every door put in the unlock standby state and a hand of the holder of the hand-held device touching a door handle of any specific door, a touch sensor employed in the door locking control device detects the touch and the door locking control device unlocks the specific door to allow the holder of the hand-held device to enter the vehicle compartment.
In addition, when the holder of the hand-held device gets off from the vehicle through a door of the vehicle after turning off an engine, a detection area of the hand-held device moves from the compartment of the vehicle to the outside thereof. At that time, when a door locking switch provided at a location in close proximity to the door handle of the door is operated, the door is locked.
In accordance with the above conventional vehicle door control system, the holder of the hand-held device is capable of locking and unlocking every door of the vehicle without manually operating a hand-held device and, thus, enjoying enhanced user friendliness of the vehicle door control system.
In recent years, the number of vehicles having an automatic door opening/closing apparatus has been increasing. The automatic door opening/closing apparatus automatically opens and closes a slide door or a rear door by using typically an electric motor as a motive power source. Such a vehicle may also have a vehicle door control system described above. In this case, the vehicle door control system and the automatic door opening/closing apparatus operate independently of each other.
That is, the automatic door opening/closing apparatus normally operates when an opening/closing switch is operated or automatically opens a door of the vehicle when the door is opened manually to a predetermined level of opening or a level higher than the predetermined level after the door is put in an unlocked state. On the other hand, the vehicle door control system operates to lock or unlock a door through duplex communications between the hand-held device and the vehicle-side unit as described above. In this way, the vehicle door control system and the automatic door opening/closing apparatus operate independently of each other although both the vehicle door control system and the automatic door opening/closing apparatus control the same vehicle door.